To get away with RZ style, you could paint the top section of the side panels on the same diagonal line as the rear section lower edge. That would visually change the shape.

You could also try the 500 style but move it lower to continue a thin line under the seat something like this RD400 but make a thin black/white line continue the lower edge of the black section to link front and rear physically as well as visually.

I'm sure others will have better ways to show that or can offer alternate colors.